Apparatus for electrical treatment of gases



W. A. SCHMIDT AND L. BRADLEY.

APPARATUS EoR ELECTRICAL TREATMENT 0E GASES.

APPLICATION FILED IUNE 24, 1915.

1,329,859, Patented Feb. 3,1920.

'uents from gases.

UNITED sTATEs PATENT oFFicE.

WALTER'AUGUST SCHMIDT, OF LOS ANGELES, CALIFORNIA, AND LINN BRADLEY, 0F EAST ORANGE, NEW 1rEiIEtSEY', ASSIGNORS TO RESEARCH CORPORATION, OF NEW YORK, N. Y., A CORPORATION OF NEW YORK.

APPARATUSFOR ELECTRICAL TREATMENT 0F GASES.

spcification of Letters Patent Patented Feb. '3, 4i920.

Original application led July 23, 1914, Serial No. 852,584. Divided and this applicatonled .Tune 24, 1916. Serial No. 105,767.

To all lwhom t may concern:

Be it known that we, 'WALTER AUGUST SCHMIDT and LINN BRADLEY, citizens. of the United States, residing, res ectively, at Los Angeles, in the county of s Angeles and State of California, and at East Orange, in the county of Essex and VState of- New Jersey, have invented anew and useful Apparatus for Electrical Treatment of Gases, of which the following is a specification; f Y

Thisapplication is a division of our application Ser. No. 852,584, filed July '23, 1914, now Patent No. 1,204,906, for method and means for recovering certain' constit- The present invention'relates to an apparatus for subjecting gases to the action of an electric discharge or of an electric field, for the purpose of precipitating suspended particles therefrom, or for other purposes.

The main object 0f the present invention is to provide improved apparatus for suoli electrical treatment of gases, and particularly to provide 'improved means for conducting the gas through the-electrical field, and for controlling the temperature, humidity and pressure of the gas in passing through the electrical field.

The accompanying drawings illustrate embodiments of our invention, and refer.- ring thereto:

Figure 1 is a' vertical section 'of an ap-l paratus suitable for use in connection with therecovery of arsenic or other condensable constituents from the flue-gases of an ore roaster, this apparatus being adapted to per form two successive precipitations, for removal, successively, of the solid suspended dust and of the condensable constituent( Fig. 2 is a; vertical section of a precipitating apparatus adapted for v use where a Hplurality of condensable constituents are to be precipitated and recovered separately.

Referring to Fig. 1, the apparatus therein shown comprises a roaster or furnace 1, for roasting or4 heating the iue dust, ore orother material, means for conducting awayl the gases from such roaster or furnace, and. a plurality ofv precipitating devices2 and 2 connected to receive such gases and adapted to perform successive precipitating actions thereon. The furnace or roaster may be of any usual or suitable construction, compriscontrol the .tempera-ture.

Each precipitator comprises a suitable ing, for example, a combustion chamber 3 and a mechanical roaster chamber 4, tol

which the ore, flue dust or other material in a divided condition, issupplied by a hop-'v per or feed means. vSuitable pipe connections 10, 11.and 12 able iiue or stack, a blower 13 being provided at any desired point in such connections for drawing or forcing the gases through the precipitators. A damper v9 is lprovided in pipe 11 for regulating the intensity of draft, and valved air-inlet means 14 is provided for admitting cool air from the outside to this pipe, so as to properly casingfor chamber, formed for example, as a series vof pipes- 15, connected to top and bottom manifolds or headers 16 and 17, and

collecting and discharge electrodes are pro-l vided in each precipitator, the pipes 15, forv example, constituting the collecting 4elec-l trodes, and the discharge electrodes consisting of Fine wires 18 suspended from insulated supports 19, and tensioned by Weights 18 at their lower ends. An insulated spacv ing frame 19 may be provided for retainingy wires 18 in position. lConnections are made.v

to said electrodes from a source of high tension unidirectional current, for example, a.

step-up transformer'20 and a rectifier 21 connected therewith, said rectifier-'and the collecting electrodes having ground connections and the highv tension side of the rectifier being connected by a wire 24: to the supports 19 for .the discharge electrodes 18. .I

Suitable means 25 are provided at the bot-Y tom of each precipitator, for recovering and v discharging the precipitated substance.

The following example will serve to illustrate the operation of the above described A apparatus as applied to metallurgical work.

In roasting certain'ores, having a high ar- .senic content, gases are given olf which'contain, among other constituents, the products of combustion., which in most cases will lbe high in sulfur dioxid,l nitrogen, etc.,l and volatilized arsenious oxid, which lin many cases will be valuable. for recovery, ifit ins. largequantities of arsenic in the form of can be recovered comparatively pure. The gases passing from the roaster also carry large quantities of dust suspended therein and the presence of this dust interferes with recoveryi'of the arsenic in pure condition from the gases, as it tends to contaminate the arsenic product. Our invention provides for recovery of the arsenic, substantially free from contamination by flue-dust, in the following manner;

"The ore is heated, or roasted in the furnace or roaster 1 and the arsenic 'content of the ore is thereby carried off, in the form of arsenious oxid, in the gases which pass from the roaster to the first precipitator'Q, together with the other products of combustion and with the. dust carried over metravel toward the collecting electrodes, on

which they are precipitated, the dust so precipitated being removed from the electrodes from time to time in any suitable manner. This operation leaves the gases in clean eondition. as far as any solid or liquid particles are concerned, and the clean gases then pass through the pipe 11, wherein they are cooled by any suitable means, .for example, by admitting cool air from the outside, throughthe ports or vvalved inlets 14, so as to reduce the temperature, of the gases below the condensation or sublimation point of the arsenic, which then condenses in a fume or cloud lof suspended particles. The gases, with the fume of arsenic suspended therein,

are then .forced by the blower 13 to the seeond preclpitator 2 wherein the arsenic fume is precipitated by electrical action in a manner similar to the action i'n precipitator 2 as above described and is recovered substantia-ily free. from dust. this precipitated arsenic being removed from the collecting electrodes and from the easing of the precipitator either continuously or from time to time, by any suitable means.

In the above described apparatus the manifolds or headers 16 and 17 are shown as extending laterally beyond the vertical pipes or Aflues 15. so that the insulated supports are spaced from the walls of the headers sufficiently to permit electrical discharge between these parts. The stack or outlet 1Q is mounted or supported directly on vthe upper manifold or header 16 of treater 2 and is of a cross-section less than the total cross-section of fines 15 of said treater, so that there is sufficient constriction at the outlet of treater 2 to enable a condition of appreciable pressure to be maintained wit-hin the treater. by the operation of the blower 13, while af the same time, said blower draws the gas from treater 2 so as to maintain a condition of suction in said treater. This apparatus therefore provides for electrical treatment of the gas at a relatively low pressure, followed by treatment at a higher pressure. and this increase of pressure may serve to control the condensation of a gas'- eous constitutent. AXfter the gas has been subjected to electrical action in the first treater so as to precipitate any material suspended therein. it may be subjected to a greater pressure in the second treater, the temperature being at the same time lowered, if necessary, so as to condense a readily condensable constituent in the gas, partly or wholly by the effect of such increased pressure, and the resulting liquid or solid particles are then precipitated by the action of the electrical field in 'the second treater.

The apparatus above described provides for subjecting the gases to two suecessive` precipitating actions. and any desired nunr ber of treaters may be, included in series in this way to operate successively on the, In carrying out a three stage operation, the apparatus shown in Fig. 2 may be used, the pipe 10 inthis case leading fromthe roaster or furnace flue to the first precipitator, and the several precipitators 2. 2. and 2 being connected in series by suitable piping, a blower '13 being provided for forcing or drawing the gases through the apparatus. In some cases, for example in the case of sulfuric acid precipitation` it may be desirable to humidity theI gases to facilitate the condensation. and for this purpose the pipe 11 between the second and third precipitating devices may be provided with water supply means 29 for spraying water into the. gas, as well as with the air-admission means 14". In some eases the cooling may be effected by liquid spray alone without air admission. or it may be effected bv other means. In the operation of this apparatus, the dust or solid or liquid suspended matter passing into the apparatus from the roaster or furnace is first precipitated by the action of t-he first precipitatr'ir 2, the gases are then cooled by admission of air in the piping l1 so as to condense the second condensate. for example. sulfuric acid, which is then precipitated by electrical action in the third precipitator 2". The sulfuric acid may be drawn off from this precipitator, for-use. but in some cases the object of the removal of the sulfuric acid from the gases may be only to avoid its presence in vthe efiiuent to the atmosphere.

The apparatus shown in Fig. 2 may, for example, be applied to the treat-ment of gases from a roasting furnace which contains two components which it is desired to remove. such as arsenious acid and sulfuric acid. As applied to the treatment of gases with this material, the dust or solid or liquid suspended matter passing into the appara-- tus from the roaster or furnace is precipitated by the action of the first precipitator 2. The gases are then cooled by admission of air through pipes ll into pipe 11, the first condensation product, for example, arsenic, being thereby condensed and immediately thereafter precipitated in the second precipitator 2. The exit gases from this precipitator are then further cooled by admission of water or water and air in the pipe ll so as to condense the second condensate, for example, sulfuric acid, which is then precipitated by electrical act-ion in the third precipitator 2".

What ewe claim is 1. In an apparatus for electrical precipitation of suspended particles from gases, in let and outlet manifold chambers. a plurality of pipes extending between said manifold chambers, discharge electrodes in said pipes and means in the lower chamber for collecting and withdrawing material deposited in said pipes.

2. In an apparatus for electrical precipitation of suspended particles from gases, ai lower manifold chamber, an upper manifold chamber, a plurality of vertical pipes communicating at their lower ends with said lower manifold chamber and at their upper ends with the upper manifold chamber, an insulated support extending within said upper manifold chamber and a plurality of discharge electrodes hung from said su port and extending respectively within said pipes.

3. An apparatus for electrical precipitation of suspended material from gases, comprising lower and upper manifold chambers, collecting electrodes consisting of vertical pipes connecting and communicating withA said manifold chambers, said manifold chambers being provided with connections for maintaining How of gases through said pipes, an insulated support mounted within the upper manifold chamber, discharge electrodes consisting of wires hung from said support and extending respectively withinv said pipes and into said lower manifold chamber, tensioning weights at the lower ends of said wires and insulated spacing-means within said lower manifold chamber for holding said discharge electrodes in spaced relation.

4. In an apparatus' for electrical treatment of gases, al plurality of pipes each having substantially closed side-walls, manifold' chambers at opposite ends of said pipes, in-

' charge through the sulated support-s mounted within said manifold chambers and electrodes mounted on on the gas. gas-connections whereby said gas-receiving means are connected to receive the gas successively and blower-means between said gas-receiving means to maintain a condition of suction in one of said gasreceiving means and a condition of pressure in the other of said gas-recei ving means.

7. An apparatus for electrical treatment of gases, comprising a gas-receiving means provided with electrodes for action on the and with means for admitting gas to said gas-receiving means and means for drawing gas from said gas-receiving means to maintaina condition of suction therein.

8. Apparatus for recovering certain constituents from gases4 comprising a plurality of devices for producing anv electric discharge through the gasto precipitate suspended particles therefrom, means for conducting the gas successively through said precipitating devices and means interposed in the path of the gas between'said precipitating devices for maintaining therein a difference of pressure.

9. Apparatus for recovering certain constituents fr onigases, comprising a plurality of devices for producing an electric disgas to precipitate suspended particles therefrom, means for conducting the gas successively through said precipitating devices and a blower interposed in the path. of the gas between said precipitating devices for maintaining a relatively higher pressure in the second precipitator.

l0. Inan apparatus for electrical separation .of certain constituents from gases, a plurality of gas-receiving means, means for passing the "gassuccessively through said gas-receiving means, means for increasing the pressure of the gas as it. passes from one gas-receiving meansto the next gas-receiving means to control 'condensation of a gaseous constituent-'and to form particles suspended in the gas and electrical means in each of the said gas-receiving means for producing electrical fields therein to precipitate particles suspended in the gas.

IVALTER AUGUST SCHMIDT. LINN BRADLEY. 

